Apparatus for speed control



May 8, 1934. L. O. HEATH Re. 19,157

I APPARATUS FOR SPEED CONTR OL Original Filed Jan. 18. 1929 4 Sheets-Shee 1 INVENTOR.

ATTORNEY.

May 8, 1934-. I L, Q A H I Re. 19,157 I APPARATUS FOR SPEED CONTROL Original Filed Jan; 18. 1929 4 heets-Sheet 2 ria .L -m 11mm i o 6 "7 7 48 1 ATTORNEY.

' 1 oxm May 8, 1934. o. HEATH APPARATUS FOR SPEED CONTROL Original Filed Jan. 18. 1929 4 Sheets$heec I5 INIV NlTORJ ATTORNEY.

L. O. HEATH APPARATUS FOR SPEED CONTROL May 8, 1934.

Original Filed Jan. 1929 4 Sheets-Sheet 4 INVENTOR.

BY Y

154 ATTORNEY.

Reissued Ma s, 1934 UNITED STA APPARATUS FOR SPEED coN'raoL Leslie 0. Heath, Philadelphia, Pa., assignor to Leeds & Northrup Company, Philadelphia, Pa., a corporation of Pennsylvania Original No. 1,897,376, dated February 14, 1933,

Serial No. 333,330, January 18, 1929. Application for reissue September 7, 1933, Serial No.

24 Claims.

. My invention relates to a method of and apparatus for controlling a condition or magnitude of a condition, 'as speed or frequency, particularlyof electric generating systems. In the eigercise of my invention-a control is effected jointly by, or in accordance with effects produced respectively by, or in accordance with, an instantaneous value, specifically an instantaneous departure from a standard or predetermined magnitude, and by, or in accordance with, an integrated value, specifically-an integrated departure from the standard or predetermined magnitude.

More particularly, the motive-energy supplied to a prime mover, as a turbine, driving for example a generator, specifically an alternator, is controlled jointly-in accordance with the in: stantaneous difference between the actual frequency of alternating current and a desired frequency, and the integrated difference between the average frequency and the desired frequency.

My invention resides in the methods and apparatus hereinafter describedland claimed. i

For an understanding of, my invention and of some of the various forms it may take, reference is to be had to the accompanying drawings, in which:

Fig. 1 diagrammatically illustrates one form of my invention as utilized to control an elecilo'trical generating unit.

Fig. *2 is a perspective view -of a controller mechanism adapted to be'used in the system shown in Fig. 1.

Fig. 3 illustrates in diagrammatic form another embodiment of my invention.

Figs. 4 and 5 are perspective views of controller-recorder mechanisms adapted for use in the system of Fig. 3. I

Figs. 6, "l and .8 show diagrammatically other forms of myinvention.

Referring to the drawings, in Fig. 1 the altertor A-supplying electrical energy to the line L driven by a prime mover P, for example a turbine, whose speed is controlled in accordance with position of the valve V by any suitable governor mechanism G. A synchronous motor S drives one shaft 1' of differential gearing D,

--of any suitable type, having a second shaft 2 rotated. at a constant speed, by suitable chrono- 59 metricmechanism C. Difference in speedof rctation of the'shafts 1 and 2 as effected, for

example, by changein frequency of the alternator-iii due to change in load upon lineL, or other cause', eflects rotation of shaft 3 of the ggldifferential gearing D in one direction or the other depending upon the sense of change of speed of shaft 2 with respect to shaft 1, which movement is utilized as hereinafter described.

A balanced network N, for example, a fre-' quency responsive Wheatstone bridge of the type described and claimed in co-pending Wunsch application Serial No. 18,794, filed March 27, 1925, is connected between the output conductors of alternator A. When the frequency of .the alternator A is of the desired or predetermined value, the network of bridge N is balanced and there is no flow of current through the deflecting instrument 1. Upon increase or decrease of frequency, the bridge is unbalanced and there is flow of current through the galvanometenI in a direction depending upon the sense of change. Movement of the ovable structure of the galvanometer is communicated by suitable mechanical connections generically indicated by the dotted shaft 4, tothe movable contact member 5 of a reversing switch controlling the energization and direction of rotation of the motor Mi Accordingly as the instrument I deflects to the right or left, depending upon the sense of change of frequency, the movable contact member 5 engages either fixed contacts 6 or 'I completing a circuit from a suitable source E through motor M, to effect rotation thereof .in a sense changing the setting of the. governor G, through a suitable mechanical arrangement, to increaseor decrease the energy supplied to the prime mover P in a sense and teen extent tending to restore the speed of the alternator A and therefore its frequency, to the desired or predeterrr'iined value. i In the example illustrated, the mechanism for communicating movement of the rotatable structure'of the motor M to the operating mechanism of the valve V comprises speed-reducing mechanism generically represented gby the pulleys 8, 9 and belt 10, operable to advance the member 11 along the threaded shaft 12, changing the position of the abutment 13, with the resultant variation of the tension of the spring 14 which opposes the flyball structure 15 of the governor G driven by the turbine or prime mover P with consequent change in speed and frequency.

when the speed'of the prime mover P is governed solely .by the frequency of the alternator A, althoughit is possible to maintainveryslight difference between the actual and desired-frequency,

quency will be either higher or lower than the it is characteristic that the average fre-' I desired frequency. To maintaln'the average fre:

quency substantially constant and to prevent quency, is utilized to more than frequency, movement of shaft 3 which n is representative of theintegrated departure of the frequency from a standardor'desired freaflect the balance of the bridge N as by effecting movement of the contacts 1e and 17 along slide wireslil'and 19. In this modification of my invention, the direction and magnitude of current to the instrument I is determined both by the instantaneous departure and integrated departure of frequencydf the current generated by alternator A from a standard frequency represented by the speed of rotation of the clock-driven shaft 2.

\ In Fig. 2 there is disclosed one form of suitable mechanism adapted for use in the system above described'to effect control of the motor M in response to deflections of instrument I. An electric motor 20 or other suitable source of power rotates at a substantially constant speed a shaft 21 havingthereon, or "to which is attached, a cam 22 which'engages the depending arm23 of a U-shaped member 24. pivoted byQpoints25 A lever 26 'is pivoted at its upper endson a horizontal axis and has pivoted thereto on a'hori'zontal axis at its lower end thearm 27, on each end of which is a shoe 28 of metal or the like, frictionally engaging a fixed metal disc 29. Secured upon the shaft 21 is a cam 30. which periodically engages the lever 26 and moves it outward y. in opposition to a spring. not shown, thereby lifting the. shoes 28 from disc or plate 29, the spring returning the shoes into engagement with the disc after predetermined rotation of cam 30. Upon the member 24 is secured element 31, whose upperedge is inclined outwardly from the center.

Disposed immediately above the upper, inclined edge of member 31 is. the needle or pointer, 32 of the deflecting instrument I- Directly above needle 32 and beneath whichit normally freely swings are the members 33, 33 pivoted at 34', 34,

fleets in one direction or the and extending toward each other, leaving a gap of sufllcient width between their inner ends for free entry of the pointer 32 when in balanced or zero position, corresponding with a balance of the Wheatstone bridge N of Fig. 1.- y

The needle 32 normally swings freely between the upper edge of member 31 and the members- 33, 33,'which latter have the downwardly extending arms 35, 35, biased toward whether by spring 36.

Attached to the lower end of the arm or lever 26 is a triangular plate 37 carrying thespins 36, 33, cooperating with the lower ends of the arms 35, 35. At opposite ends of the arm 27 are the lugs 39, 39, adapted to be engaged by the cams 40, 40, similar in shape and similarly positioned and secured upon the shaft 21. The cams 40,

40 are of suitable conducting material and are insulated, from. the shaft 21. Suitable contact brushes 41, 41 are in cons t electrical engagement with cams 40, 40, ands third brush 42 is in constant electrical engagement with disc 29 and therethrough with arm 27. which corresponds to the movable switch member 5 of Fig. 1, the cams 40, 40 corresponding to the contacts 6 and 'l of the reversing switch. When the galvanometer pointer 32 is in its central position due to balanced condition- 91 the bridge N, either of calm 40 engage lugs 39 and de-energiaed. As the galvanometer needle 32 deother, the arm-2'! is rotated in one or theother direction bringing a ing 39, corresponding to-either contact 6 or the motor M remains 7 of Fig.-1,int'o the pith of movement of a cam 'and 17 along slidewires 40 by which it is engaged and 'moved to its original position, the extent of movement and therefore the duration of mechanical and electrical contact betweendetermined by the entent of deflection of the instrument 1 and unbalance of bridge N In this modification of my invention shown in g. 3 deflection of the instrument I and movement ofthe contact 5 is eifected solely in accordance with change of frequency. To eflect the. desired control in accordance with both the instantaneous and integrated departufe of frequency, movement of the difl'erential. shaft 3 is communicated to contact structure of the reversing switch controlling energiz'ation of motor M. For example, in whose ends are connected to reciprocable car -riage 54 passes over a pulley 47 secured to shaft 3 so that displaced longitudinally of cylinder 46, to changethe relation between the contacts 6 and 7 carried thereby and contact 5. him of this figure the disc 29 shoes 28' of arm 2'? is secured shaft 49 on which is mounted slidewire discs 50, one o'fwhich carrying the slide wire 18 engaged by the fixed contact 16, is shown. Upon deengaged by cork fiction of the pointer 32, plate 29' and slide wire.

discs 50 are rotated, the bridge eventually coming to a balance at a new position of the-contacts 16 18 M19. A cord 51 connected to contact 5 idler pulleys 52 engages'the periphery or a groove the members 40 and 39 being Fig. 4, a cord 43 or equivalent,

upon rotation thereof the carriage 54 is In' the control mecha-f to the rotatable and passingflo'ver the of pulley 53 secured to control shaft 49 to transmit motion thereof to contact 5 eifecting its movement toward or into engagement with either of contacts 6 and 'I.

Movement of carriage 54 effects change in position of contact 5 without movement of the portion of belt or cord 51 extending between the lower pair of pulleys 52'andencircling pulley 53 secured to shaft 49, as is more fully'explained in co-pending Doyle application semi No. 264,370, filed June 11, 1928.- The position of contact 5 in this modified control apparatus is, at any given time determined by magnitude and sense of -departure of the instantaneous departure and of the integrated departure of the condition controlled, as frequency, time. 0 "Alternatively as suggested by the arrangement of Fig. 5, contact 5 may be moved solely by rotation of controller shaft 49 and the position of contacts 6 and 7 controlled by reciproca-. tion of cylinder 46 on shaft '48 by cord 43.

'Rotation of cylinder 46 and of contacts 6 and 7 shown as having increasingly greater circuinfenential' extent as the distance from the center of the cylinder is increased, is eflected in any suit-- from a standard at that" able manner,;as for example, by driving engagement betweengear 55 toshaft 48 and bevel gear 56 secured to shaft 57 driven from shaft 21 by another pair of gears 58, 59 secured respectively to shafts 5'! and 21. Duration of I engagement between contact 5 and either of cornperiods of energization of the motorM and the cylinder 46 on which extent of movement of the abutment 13 controlling the governor settingis greater as. the algebraic sum of the departure of and average frequency from the desired frequency is greater and vice versa; 1

To the shaft 49 there is also attached a pulley 60 engaged by a cord 61 or equivalent which passes over the idler pulleys 62 and moves a pen ;or stylus ,63 across the surface of recorder sheet 64 in accordance with rotation of'shaft 49 as deflected by change of instantaneous frequency.

, stantaneous frequency by mechanism similar or equivalent to that shown in Fig. i

4. a p In the modification of my invention shown in .Fig. 6 movement of the differential shaft 3 effects movement of contact 10 along a resistance '11 included in the bridge, to vary calibration thereof. The frequency at which the bridge is balanced is varied within suitable limits by shifting of contact '10 to vary the'proportion between the portions of resistance '11 included in the upper arms of the bridge N. Accordingly, the governor setting is changed to vary the speed of alternator A at which the bridge is balanced. With this modification, the mechanism may be of the controller or recorder-controller type for example, as shown in Fig. 4 or 5.

Inf Fig. '1 there is a further modified form bf my nvention, generally similar to that shown in Fig. 6 and in which movement of the differential shaft 3 moves a contact '12 into engagement'with either of fixed contacts '13 or '14 to shunt either of resistances '15 or '16 included in adjacent arms of the bridge N suitably to change the calibration thereof to an extent, which is, however, pref erably not great enough to substantially impair the accuracy of the record traced by the recorder pen 63, if used.

The bridge circuit shown in Fig.8 is similar to that shown in Fig..'1.in that there is included the resistances '15 and '16- adapted to be'shunted to be shunted, to change the calibration of the bridge. With the solenoid or electromagnet 7'1,

there is associated movable armature structure,- not shown, mechanically connected to the bridg-.'

ing contact members '18, '19 and 80. Energize.- tion of the electromagnet, as hereinafter described, efiects upward movement of contact '18 to bridge *the fixed contacts 81 and 82,- upward --movement of contact '19 to engage contacts 83 and 84, and movement of'contact member to break ,awayfrom contacts 85 and 86. Similarly, energization of the solenoid or electromagnet 8'1 effects movement of a bridging contact 88 into engagement with fixed contacts89 and 90, engagement between movable bridging contact member 91 and fixed. contacts 92 and 93, and movement of bridging contact member 94 from fixed contacts 95 and 96. Aconductor 9'1 from one terminal of a suitable source of current 98 is connected to the upper ends of solenoids '1'1 and 87 and a conductor 99 from the other terminal thereof is connected to the contacts 86 and 95 through a movable contact member 100 adapted to engage fixed contactlOl. Included in a con- .ductor between the opposite end of solenoid '1'1 and contact 96 is a movable contact 102 adapted to engage a fixed contact 103 and similarly in a conductor between the lower end of solenoid 87 and contact" 85 is included a switch member 104 adapted to engage a fixed contact 105. A cam 106 driven from the chronometric mechanism C, or equivalent, periodically moves the movable switch member 104 into engagement with fixed contact 105, for example at intervals of one minute. and a cam 10'! rotatable with the shaft of the able contact member 102 into engagement with the fixed contact 103. a

If the cam 106 engages the movable contacts 104 prior to engagementof cam 107 with movable e'ontact member 102, solenoid 8'1 is energized and moves the contact member 94 out of engagement with contacts 95 and 96 and prevents the solenoid '17 from being energized upon subsequent engagement between contacts 102 and 103 as efsynchronous motors periodically forces the movfected by cam 10'1. -The switch member 88 ample, approximately one minute, which occurs when a depression in the cam 108 driven from the synchronous motor S comes opposite the co-operating portion of the switch member 100 whereupon bridging contacts 88, 91 and 94 resume their original positions. Similarly upon increase of average frequency able contact member 102 before the cam 106 driven by the standard mechanism C engages the movable contact 104 engaging the solenoid '1'1 and. ias'above described, effecting upward movement of contact, members '18, '19 and 80. The separation of contact members 80, 85 and 86 effects a discontinuity of the circuit of solenoid 87 so that upon subsequent engagement of the switch member 104 byv cam 106 the solenoid 8'1 remains de-energized. Engagement of bridging 'eontact '18 and contacts 81 and 82 completes a holding circuit which maintains the solenoid '1'1 energized, despite continued movement of cam 1'07 and consequent separation of contacts 102 and 193. During the energization of solenoid '17, the 'movable contact member '19 in engagement with fixed contacts 83 and 84 shunts the resistance"16 of the bridge N to change the bridge calibration. After a suitable interval, the flow of Recorder mechanism such, as for example, of

; the type shown in Fig. 4, may be utilized in this" system to record frequency of the alternator A.

or line frequency.

While I prefer to change the setting or the governor G, indirectly to eifect the settings or positions of valve V, it "will be understood that the motor M, through suitable gear reduction or equivalent, may directly actuate the valve. Furthermore, my invention is not limited to the control of speed or frequency but may be utilized to control any condition or characteristic by the use of suitable instruments responsive to instantaneous and integrated departures of the condition or characteristic from a desired standard the cam 101 engages the mov-'- or to the instantaneous andintegrated values bers adapted to cooperate quency,

taneous departure from from said standard,

- work. means to thereof, which co-operate jointly to eifcct a control.

What I claim is: a v

I 1. A control system comprising a balanced network, means to eil'ect unbalance of said network in a sense determined by the sense of instana standard, means to effect unbalance of said network-in a sense corresponding to the sense of integrated departure and a control member movunbalance of said network.

I comprising a balanced netmber movablein response to un an exthe'sense of instantaneous departure from a standard, means to effect unbalance of said network in a sense and to an extent corresponding to the sense and extent of integrated departure. from said standard, and a con' trol member movable in response to unbalance of said network. I 3. A control system comprising a balanced net- .wor a member mcvableln response to unbalance of said network, structure co-operating therewith to eife'ct control, means to effect unbalance of said, network in a sense determined by the sense of instantaneous departure from a standard, and means varying the relation of said members and structure in a sense corresponding to the$nse of integrated departure from said standard.

4. A control system comprising-a balanced network, a member movable in response to unbalance of said network, structure co-operating therewith to effect control, means to effect unbalance of said network ina sense and teen extent determined by the sense and extent of'instantaneous departure from a standard, and means varying the rela: tion of said member andstructure in a sense and to an extent corresponding to the sense and extent of integrated departure from said standard.

5. A control system comprising a balanced neteifect unbalance of said network in a sense determined by the sense of instantaneous departure from a standard, and means intermittently operative to effect unbalance of said network in a sense corresponding to the sense of integrated departure from said standardsaid means jointly effecting a control.

' 6. A frequency control system comprising a balanced network unbalanced by departureof instantaneous frequency from a standard frequency in a sense determined bythe sense of said departure, means to efl'ect unbalance of said network in a sense corresponding to the sense of integrated departure from said standard frequency, and 'a frequency-controlling member movable in response to unbalance ofthe networ I. A frequency control system comprising an alternating current Wheatstone bridge, means responsive to imbalance of said bridge for controlling frequency, means for impressing affrequency to be controlled upon said bridge to eifect unbalance thereof, upon instantaneous departure from astandard frequency, unbalance of said network in a sense corresponding to the sense of integrated departure from said standard frequency.

8.. A frequency control system comprising memto effect control of fremeans responsive to departure of instantaneous'frequencyfroni a standard including an alternating current Wheatstgne bridge, and means responsive to integrated departure of frequency the control relation 0 cc of said network, means to effect my. balance of said network in a sense and to 'tent determined by mover therefor, a

and' means 'to eifect means responsive to from a standard, said said members.

nt comprising an alternator, aprimemover and a governor, a system for controlling the alternator frequency comprising members adapted to cooperate to eifect change of governor setting, analternating current Wheatstonebridge unbalanced upon departure of instantaneous frequency froma standard, and meansresponsiv to integrated departureof ire- 9. In an arrangeme quency determining Jointly with said "Wheat-T stone bridge the control relation of said members.

means jointly determining a 10. In an arrangement comprising an alternator, a prime mover controlling the alternator frequency comprising an electro-mechanical system including a Wheatstone bridge integrated departure of frequency from a standard, and means associated with said system ac- .tuated in accordance with unbalance thereof for changing the governor setting.

11. A frequency control system comprising an alternating current Wheatstone bridge, means responsive to unbalance of said bridge for controlling frequency, means for impressing a frequency to be controlled upon said bridge to efl'ectunbalance thereof upon instantaneous departure from a stan 'frequenc structure movable to vary the ratio between arms of said bridge, and means responsive to the integrated departure of the frequency from standard for moving said structure tounbalance said bridge.

12. In an arrangement comprising an alternator, a prime mover, a governor therefor, and an electric motor for changing the governorsetting, a control. system for said motor comprising a reserving switch including a rotatable structure having contacts. increasing in area from a neutral zone, a contact adapted selectively to engage said contacts, and means to effect movement of said contact to and from saidneutral zone comprising a differential system between a standard clock and a synchronous motor driven from said alternator.

13. A system comprising an alternator, a prime mover, a governor therefor, a reversible motor for changing for chan departure of frequency from standard and for periods. whose duration is "substantially proportional to the departure.

' 14. A system comprising an alternator, a prime governor for said prime mover, an electric motor for changing the governor setting, and means for changing the governor setting by steps substantially 'proportional to the departure of the instantaneous and integrated frequency from standard comprising a reversing .switch for .eflecting energization of said motor,

the departure of the instantaneous and integrated frequency from standard, and means controlled by said responsive means for controll the senseof actuation of said switch in rdance with the sense of the departure and for periods whose duration 'is substantially proportional to the departure.

and a governor, a system for.

unbalanced for instantaneourand' the governor setting and means the governor setting by steps-sub-- stantially proportional to the departure of the and integrated frequency fromI 15. In combination, a circuit controlling means, two means for independently controlling the operation of said circuit controlling means, said two means being responsive respectively to a variable quantity and teen infinitesimal calculus function of said quantity. 4

16. In combination, circuit controlling means having an effective circuit closing condition and an effective circuit opening condition, two means for each independently acting to put said circuit controlling means in the same one of said conditions, said two means being responsive respectively to a variable quantity and to an infinitesimal calculus function of said quantity.

17. In combination, apparatus having a variable quantity'to be regulated, electrically operated means for controlling said quantity, and two mechanisms for independently controlling the operation of said means, said mechanisms being responsive respectively to said quantity and to an integral function of said quantity.

18. In combination, circuit controlling means, two means for independently controlling the operation of said circuit controlling means, said two means being responsive respectively to a variable quantity and to an infinitesimal calculus function of said quantity with respect to time.

19. In combination, circuit controlling means having an effective circuit closing condition and imal calculus function of said quantity with respect to time.

20. In combination, apparatus having a variable quantity to be regulated, electrically operated means for controlling said quantity, and two mechanisms for independently controlling the operation of .said means, said mechanisms being responsiverespectively to said quantity and to an integral function oi. said quantity with respect to time.

21. A regulator having, in combination, a pair of cooperating contacts, means for moving one of said contacts in accordance with changes in the instantaneous value of a quantity to be regulated, and means for moving the other contact in accordance with changes in the integrated value of a quantity to be regulated.

22. A regulator having, in combination, a pair of cooperating contacts, means for moving one of said contacts toward the other in response to instantaneous deviations from a normal value of a condition to be regulated, and means for moving the other contact toward the first-mentioned contact in response to integrated deviations from said normal value of said condition to be regulated.

23. A regulator having, in combination, a pair of cooperable contacts, means responsive to the instantaneous value of a condition to be regulated for moving one of said contacts, a device for producing rotary movement whose speed is proportional to the instantaneous value or said condition, a source of substantially constant speed rotation, and means for moving said other contact in accordance with a difference in speed between said device and said source.

24. In combination, an electric power circuit, means for controlling the power flow in said cir-' cuit, a pair of cooperating contacts for controlling the operation of said means, means responsive to the instantaneous value of an electrical condition of said circuit for moving one of said cooperating contacts towards the other when the instantaneous value of said condition departs from a predetermined normal value, and means responsive to the integrated value of deviations from said predetermined normal value for moving the other contact toward the first-mentioned contact.

' LESLIE O. HEATH. 

